Vapor cycle compressor with variable inlet/outlet geometry

ABSTRACT

A vapor cycle compressor includes a controller section, a drive section in communication with the controller section, and a compression section operatively engaged with the drive section. The compression section includes: an inlet guide vane assembly, wherein the inlet guide vane assembly includes inlet vanes that are configured to adjust their angle of orientation; a first stage diffuser assembly downstream of the inlet guide vane assembly, wherein the first stage diffuser assembly includes first diffuser vanes that are configured to adjust their angle of orientation; a return channel assembly downstream of the first stage diffuser assembly, wherein the return channel assembly includes return channel vanes that are configured to adjust their angle of orientation; and a second stage diffuser assembly downstream of the return channel assembly, wherein the second stage diffuser assembly includes second diffuser vanes that are configured to adjust their angle of orientation.

BACKGROUND OF THE INVENTION

The present invention generally relates to vapor cycle compressors and, more particularly, to apparatus and methods of widening the operational envelope of flows in centrifugal compressors.

In a centrifugal refrigerant compressor, gas enters the compressor through a fixed inlet nozzle that directs the flow into a centrifugal impeller in such a way that the flow is uniformly distributed at a desired velocity. The flow then travels through stationary components adjacent to the impeller inlet designed to deliver the flow to the impeller with minimal pressure drop. The impellers force the gas refrigerant to spin faster and faster. The flow then leaves the impeller and typically flows through a stationary diffuser causing it to decelerate. These stationary diffusers are actually static guide vanes where energy transformation takes place, where part of velocity head turns to a pressure head. This reduction in velocity causes the pressure to rise leading to a compressed fluid.

Typical centrifugal vapor cycle compressors have a narrow operational envelope due to fixed vanes within the inlet and the diffuser. These vanes define the operational envelope of the compressor which includes the pressure ratio and the mass flow rates that are achievable. This narrow envelope provides challenges and limitations when designing an aircraft vapor cycle refrigerant system because the compressor must operate at both design and off-design conditions.

As can be seen, there is a need for improved apparatus and methods to increase the operational envelope in a centrifugal compressor.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a vapor cycle compressor comprises a controller section; a drive section in communication with the controller section; and a compression section operatively engaged with the drive section, wherein the compression section includes: an inlet guide vane assembly; wherein the inlet guide vane assembly includes inlet vanes that are configured to adjust their angle of orientation; a first stage diffuser assembly downstream of the inlet guide vane assembly; wherein the first stage diffuser assembly includes first diffuser vanes that are configured to adjust their angle of orientation; a return channel assembly downstream of the first stage diffuser assembly; wherein the return channel assembly includes return channel vanes that are configured to adjust their angle of orientation; a second stage diffuser assembly downstream of the return channel assembly; wherein the second stage diffuser assembly includes second diffuser vanes that are configured to adjust their angle of orientation.

In another aspect of the present invention, a vapor cycle compressor comprises a controller section; a drive section in communication with the controller section; wherein the drive section includes a plurality of stepper motors; and a compression section operatively engaged with the drive section, wherein the compression section includes: an inlet guide vane assembly operatively engaged with a first stepper motor; a first stage diffuser assembly downstream of the inlet guide vane assembly and operatively engaged with a second stepper motor; a return channel assembly downstream of the first stage diffuser assembly and operatively engaged with a third stepper motor; a second stage diffuser assembly downstream of the return channel assembly and operatively engaged with a fourth stepper motor.

In a further aspect of the present invention, a vapor cycle compressor comprises a controller section; a drive section in communication with the controller section; and a hermetically sealed compression section operatively engaged with the drive section, wherein the compression section includes: an inlet guide vane assembly; a first stage diffuser assembly downstream of the inlet guide vane assembly; a return channel assembly downstream of the first stage diffuser assembly; a second stage diffuser assembly downstream of the return channel assembly; wherein the inlet guide vane assembly, the first stage diffuser assembly, the return channel assembly, and the second stage diffuser assembly each have a respective set of vanes; wherein each respective set of vanes is configured with a respective orientation angle that can be varied independently of one another.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an exterior of a vapor cycle compressor according to an embodiment of the present invention.

FIG. 1B is a perspective view of an interior of the vapor cycle compressor of FIG. 1A.

FIG. 2 is a partial, cross-sectional schematic view of a vapor cycle compressor according to an embodiment of the present invention.

FIG. 3A is a perspective view of a compression section of a vapor cycle compressor according to an embodiment of the present invention.

FIG. 3B is a cross sectional view of the compression section of FIG. 3A.

FIGS. 4A-4B are perspective views of an inlet guide vane assembly of a vapor cycle compressor according to an embodiment of the present invention.

FIGS. 5A-5B are perspective view of a variable vane assembly of a vapor cycle compressor according to an embodiment of the present invention.

FIG. 6 is a cross sectional view of a variable vane assembly operatively engaged with a stepper motor assembly according to an embodiment of the present invention.

FIG. 7 is a perspective view of a first stage impeller assembly of a vapor cycle compressor according to an embodiment of the present invention.

FIG. 8 is a perspective view of a second stage impeller assembly of a vapor cycle compressor according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Various inventive features are described below that can each be used independently of one another or in combination with other features. However, any single inventive feature may not address any of the problems discussed above or may only address one of the problems discussed above. Further, one or more of the problems discussed above may not be fully addressed by any of the features described below.

Broadly, the present invention provides a vapor cycle compressor that allows angle variation of one or more of inlet guide vanes, return channel vanes, and diffuser vanes. That can provide a wider operational envelope, an improvement in the coefficient of performance, and the ability to use different refrigerants in the compressor without changing the design. This invention allows independent variability of the inlet and outlet geometries within a centrifugal refrigerant compressor, a hermetically sealed drive mechanism, redundancy for the drive mechanism, control logic that adjusts the vanes based on performance requirements, and a compact light weight mechanism.

Generally, in the present invention, a compression section is arranged with the impellers front-to-back, with an internal crossover between stages to minimize overall compressor size and weight. Variable inlet guide vanes in conjunction with variable diffuser vanes are utilized in both the first and second stages. Each variable vane mechanism is driven by redundant stepper motors connected to a common shaft. The common shaft contains a worm that drives a geared section of a unison ring. The unison ring, in turn, rotates the vanes in one direction or an opposite direction.

Although described in the exemplary context of an aircraft, the present invention can be used in other environments.

In FIG. 1A, an exemplary vapor cycle compressor 100 can be affixed to a support via mountings 107. The compressor 100 may include a drive section 101, a compression section 102 operatively engaged with the drive section 101, a controller section 120 in communication with the drive section 101, and a motor section 121 operatively engaged with the compressor section 102. The controller section 120 and the motor section 121 may be hermetically sealed in a cover/housing 103.

In embodiments, the drive section 101 may include a stepper motor assembly 105 that can be hermetically sealed. The stepper motor assembly 105 may include a plurality of stepper motor subassemblies 105 a. One or more of the subassemblies 105 a may include a stepper motor connector 105 b and a stepper motor housing 105 c. The stepper motor connector 105 b may connect to power from a separate or internally derived source. One or more of the stepper motor subassemblies 105 a may further include a stepper motor, a worm, a worm shaft, and a worm gear, as described below.

The compression section 102, according to embodiments, may include an inlet subsection 102 a and an impeller/diffuser subsection 102 b. The inlet subsection 102 a may include a compressor inlet 104 configured to receive a vapor refrigerant. The inlet subsection 102 a may further include an inlet guide vane assembly described below.

The impeller/diffuser subsection 102 b, in embodiments, may include an upstream first stage impeller assembly, a downstream first stage diffuser assembly, a downstream return channel assembly, a downstream second stage impeller assembly, and a downstream second stage diffuser assembly described below. The impeller/diffuser subsection 102 b may also include a sub-cooling inlet 106 that is configured to increase cooling performance and extend compressor flow range.

In FIG. 1B, according to embodiments, the controller section 120 of the compressor 100 may include a digital signal processor 113 that is configured to provide localized compressor torque and speed control which includes stepper motor function, and a high power switch module 116 that is configured to provide control of the main electric motor 121. A current sensor transducer 112 can be configured to measure power into the motor section 121, a motor bus bar 114 can be configured to distribute current, and a stud seal terminal 115 can be configured to pass electric current from the exterior of the compressor to the interior of the compressor. A capacitor 118 can be configured to maintain constant controller DC link voltage, capacitor bus bar 117 can be configured to supply or distribute link voltage, and a power input terminal 119 can be configured to receive power to the compressor.

In FIG. 2, according to embodiments, a vapor cycle compressor 200 may include a drive section 201, a compression section 202, a motor section 221, and a controller section (not shown), all of which can be similar to that described in relation to FIGS. 1A-1B. Accordingly, reference numbers in FIG. 2 correspond to like reference numbers in FIGS. 1A-1B.

The drive section 201 may, in embodiments, include a stepper motor assembly 205 which may be operatively engaged with an inlet guide vane assembly 225, a first stage impeller assembly 226, a first stage diffuser assembly 228, a return channel assembly 229, and a second stage diffuser assembly 232, all of which can be part of the compression section 202.

The stepper motor assembly 205 may include a plurality of stepper motors 205 e. Each stepper motor 205 e may be paired with and be operatively engaged to each of the inlet guide vane assembly 225, the first stage diffuser assembly 228, the second stage diffuser assembly 232, and the return channel assembly 229.

Still referring to FIG. 2, the motor section 201 may, in embodiments, include a motor 221 a that can have a stator 221 b and a rotor 221 c. A tie rod 224 may extend from within the motor 221 a, through a thrust bearing disk 230, and into the compression section 202. Thereby, the motor section 201 may drive the first stage and second stage impeller assemblies 226, 227 of the compression section 202. In so doing, a vapor refrigerant may be compressed while flowing in a vapor refrigerant path 231 through the inlet guide vane assembly 225, then through the first stage impeller assembly 226, then through the first stage diffuser assembly 228, then through the return channel assembly 229, then through the second stage impeller assembly 227, and then through the second stage diffuser assembly 232.

In FIGS. 3A-3B, a compression section 302 and a stepper motor assembly 305, according to embodiments, are shown. The compression section 302 may be similar to that described in relation to FIGS. 1A-1B and 2. Accordingly, reference numbers in FIGS. 3A-3B correspond to like reference numbers in FIGS. 1A-1B and 2.

The compression section 302 may include a compressor inlet 304 that can direct a vapor refrigerant into an inlet guide vane assembly 325. From there, vapor refrigerant may be compressed in two stages. A first compression stage may include a first stage impeller assembly 326 directly downstream of the inlet guide vane assembly 325. A first stage diffuser assembly 328 may be directly downstream of the first stage impeller assembly 326.

The first compression stage and the inlet guide vane assembly 325 may be within a housing 338. The housing 338 may further enclose the stepper motor assembly 305 to provide hermetic sealing of the compression section 302 and the stepper motor assembly 305.

In embodiments, the compression section 302 may include a return channel assembly 329 (having a return channel guide vane 329 a), directly downstream of the first stage diffuser assembly 328, and that may direct vapor refrigerant from the first compression stage and into the second compression stage. The second compression stage may include a second stage impeller assembly 327 directly downstream of the return channel assembly 329. A second stage diffuser assembly 332 may be directly downstream of the second stage impeller assembly 327. The second stage compression may be within a housing 337 for hermetic sealing.

In the compression section 302, according to embodiments, an inlet 306 may provide vapor refrigerant to an inlet scroll 333 that can be configured to provide additional flow to the second stage, while an outlet scroll 334 may be configured to direct vapor refrigerant out of the second compression stage, via an outlet 336. The inlet and outlet scrolls 333, 334 may be within the housing 337. A housing 335 may enclose a thrust disk 330.

Still referring to FIGS. 3A-3B, the stepper motor assembly 305 may be similar to that described in relation to FIGS. 1A-1B and 2. Accordingly, reference numbers in FIGS. 3A-3B correspond to like reference numbers in FIGS. 1A-1B and 2.

According to embodiments, the stepper motor assembly 305 may include a plurality of stepper motor subassemblies, each of which may include a stepper motor 305 e that can each drive a worm shaft 305 f. In turn, the worm shaft 305 f may rotate a worm 305 d which, in turn, can rotate a worm gear 305 g. A respective stepper motor subassembly, and specifically a respective worm gear 305 g, may be operatively engaged to the inlet guide vane assembly 325, the first stage diffuser assembly 328, the return channel assembly 329, and the second stage diffuser assembly 332 as described below.

FIGS. 4A-4B depict an exemplary inlet guide vane assembly 425. The inlet guide vane assembly 425 may be similar to that described in relation to FIGS. 2 and 3A-3B. Accordingly, reference numbers in FIGS. 4A-4B correspond to like reference numbers in FIGS. 2 and 3A-3B.

According to embodiments, the inlet guide vane assembly 425 may be configured to receive a vapor refrigerant flow 431 which can pass through a plurality of upstream, non-variable inlet support struts 425 e. The refrigerant flow 431 may then move to and through a plurality or set of downstream variable inlet vanes 425 a.

The set of inlet vanes 425 a, and each individual inlet vane 425 a in such set, can be characterized by an angle of orientation. The angle of orientation may be measured by an angle about which each inlet vane may rotate around an axis of rotation. The axis of rotation may be substantially perpendicular to a longitudinally extending sleeve 425 f that may receive a tie rod, such as tie rod 224. As described below, the angle of orientation may be adjusted clockwise and counterclockwise.

In embodiments, the inlet guide vane assembly 425 may include an inlet housing 425 d that can enclose the inlet vanes 425 a and the inlet support struts 425 e. A face gear 425 b may extend around the entire circumference of the inlet housing 425 d. The face gear 425 b may support one or more worm gears 405 g. One or more sector gears 425 c may be spaced around the entire circumference of the inlet housing 425 d. Also, one or more of the sector gears 425 c may be operatively engaged to the face gear 425 b. As further described below, movement of the worm gear 405 g can cause a variation of the angle of rotation of the inlet vanes 425 a.

FIGS. 5A-5B depict an exemplary first stage diffuser assembly 528. The first stage diffuser assembly 528 may be similar to that described in relation to FIGS. 2 and 3A-3B. Accordingly, reference numbers in FIGS. 5A-5B correspond to like reference numbers in FIGS. 2 and 3A-3B.

According to embodiments, the first stage diffuser assembly 528 may be configured to receive a vapor refrigerant flow 531, which can be, for example, from a first stage impeller assembly (not shown). The first stage diffuser assembly 528 may include a plurality or set of downstream variable diffuser vanes 528 a that receives the refrigerant flow 531.

The set of diffuser vanes 528 a, and each individual diffuser vane 528 a in such set, can be characterized by an angle of orientation. The angle of orientation may be measured by an angle about which each diffuser vane may rotate around an axis of rotation. The axis of rotation may be substantially parallel to a longitudinally extending tie rod, such as tie rod 224, which can extend through an aperture 528 g. As described below, the angle of orientation may be adjusted or varied.

In embodiments, the first stage diffuser assembly 528 may further include a diffuser plate 528 b that can support on one planar side thereof, via connectors 528 c, the diffuser vanes 528 a. On an opposed planar side of the diffuser assembly 528, a unison ring 528 d may be operatively engaged to one or more driver arms 528 e. The unison ring 528 d may also be operatively engaged to one or more worm gears 505 g. One or more rollers 528 f may rotatably support the unison ring 528 d at an inner circumference thereof.

Although FIGS. 5A-5B depict an exemplary first stage diffuser assembly, it should be understood that similar components and the assembly thereof can also be used for one or both of the return channel assembly and the second stage diffuser assembly, such as that depicted in FIGS. 2 and 3A-3B.

FIG. 6 depicts an exemplary stepper motor assembly 605 operatively engaged to a plurality or set of variable vanes, such as those that may be included in one or more of the first stage diffuser assembly, the second stage diffuser assembly, and the return channel assembly, as described above with regard to FIGS. 2, 3A-3B, and 5A-5B.

The stepper motor assembly 605 may include one or more stepper motor subassemblies 605 a. One or more of the stepper motor subassemblies 605 a may include one or a pair of redundant stepper motors 605 d connected by a worm shaft 605 f there between. Accordingly, if one of the paired stepper motors 605 d fails, the other of the paired motors may be used. A stepper motor connector 605 b may be provided at each stepper motor 605 d to provide power.

In embodiments, one or more of the stepper motor subassemblies 605 a may include at least one worm 605 e that is operatively engaged to at least one worm gear 605 g which, in turn, can be operatively engaged to the set of variable vanes (not shown).

The variable vanes can be supported by a plate 628 b. The plate 628 b may support one or more driver arms 628 e that can be operatively engaged, via one or more connectors 628 c, to one or more of the variable vanes. Also, one or more of the driver arms 628 e may be operatively engaged to a unison ring 628 d. One or more rollers 628 f may support the ring 628 d.

In operation, a single stepper motor 605 d, or one of the paired stepper motors 605 d, may rotate the worm shaft 605 f. In turn, the worm 605 e may rotate, which can cause the worm gear 605 g to rotate. The rotation of the worm gear 605 g causes the unison ring 628 d to rotate. In turn, one or more of the driver arms 628 e can rotate. Via the connector 628 c associated with the rotating arms 628 e, one or more of the vanes rotate about a longitudinal axis of the connector 628 c.

The use of paired stepper motors can also be employed in rotating inlet vanes of an inlet guide vane assembly, such as that depicted in FIGS. 4A-4B. One of the paired stepper motors can—via a worm shaft, worm, and worm gear 405 g—rotate the face gear 425 b. In turn, one or more sector gears 425 c can rotate. Via one or more connectors 425 g, which are operatively engaged to one or more inlet vanes 425 a, one or more of the inlet vanes 425 a can rotate about a longitudinal axis of the connector 425 g.

It can be appreciated that the stepper motor assembly, upon control from the controller section, can rotate one or more of the sets of variable vanes of the inlet guide vane assembly, the first stage diffuser assembly, the return channel assembly, and the second stage diffuser assembly.

FIG. 7 depicts an exemplary first stage impeller assembly 726 which may contain a plurality of blades 726 a enclosed in a housing 726 c. In this exemplary embodiment, the blades cannot be varied in their angle of orientation.

FIG. 8 depicts an exemplary second stage impeller assembly 827 which may contain a plurality of blades 827 a enclosed in a housing 827 c. A cooling inlet 827 d and a cooling outlet 827 e may be provided. In this exemplary embodiment, the blades cannot be varied in their angle of orientation.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

We claim:
 1. A vapor cycle compressor, comprising: a controller section; a drive section in communication with the controller section; and a compression section operatively engaged with the drive section, wherein the compression section includes: an inlet guide vane assembly; wherein the inlet guide vane assembly includes inlet vanes that are configured to adjust their angle of orientation; a first stage diffuser assembly downstream of the inlet guide vane assembly; wherein the first stage diffuser assembly includes first diffuser vanes that are configured to adjust their angle of orientation; a return channel assembly downstream of the first stage diffuser assembly; wherein the return channel assembly includes return channel vanes that are configured to adjust their angle of orientation a second stage diffuser assembly downstream of the return channel assembly; wherein the second stage diffuser assembly includes second diffuser vanes that are configured to adjust their angle of orientation.
 2. The compressor of claim 1, further comprising a stepper motor assembly operatively engaged with the inlet guide vane assembly.
 3. The compressor of claim 1, further comprising a stepper motor assembly operatively engaged with the first stage diffuser assembly.
 4. The compressor of claim 1, further comprising a stepper motor assembly operatively engaged with the return channel assembly.
 5. The compressor of claim 1, further comprising a stepper motor assembly operatively engaged with the second stage diffuser assembly.
 6. The compressor of claim 1, further comprising a first stage impeller assembly intermediate the inlet guide vane assembly and the first stage diffuser assembly.
 7. The compressor of claim 1, further comprising a second stage impeller assembly intermediate the return channel assembly and the second stage diffuser assembly.
 8. A vapor cycle compressor, comprising: a controller section; a drive section in communication with the controller section; wherein the drive section includes a plurality of stepper motors; and a compression section operatively engaged with the drive section, wherein the compression section includes: an inlet guide vane assembly operatively engaged with a first stepper motor; a first stage diffuser assembly downstream of the inlet guide vane assembly and operatively engaged with a second stepper motor; a return channel assembly downstream of the first stage diffuser assembly and operatively engaged with a third stepper motor; a second stage diffuser downstream of the return channel assembly and operatively engaged with a fourth stepper motor.
 9. The compressor of claim 8, wherein the inlet guide vane assembly includes a plurality of inlet vanes, at least one of which has an angle of orientation that is adjustable by the first stepper motor.
 10. The compressor of claim 8, wherein the first stage diffuser assembly includes a plurality of first diffuser vanes, at least one of which has an angle of orientation that is adjustable by the second stepper motor.
 11. The compressor of claim 8, wherein the return channel assembly includes a plurality of return channel vanes, at least one of which has an angle of orientation that is adjustable by the third stepper motor.
 12. The compressor of claim 8, wherein the second stage diffuser assembly includes a plurality of second diffuser vanes, at least one of which has an angle of orientation that is adjustable by the fourth stepper motor.
 13. The compressor of claim 8, wherein the drive section is hermetically sealed.
 14. The compressor of claim 8, wherein the compression section is hermetically sealed.
 15. A vapor cycle compressor, comprising: a controller section; a drive section in communication with the controller section; and a hermetically sealed compression section operatively engaged with the drive section, wherein the compression section includes: an inlet guide vane assembly; a first stage diffuser assembly downstream of the inlet guide vane assembly; a return channel assembly downstream of the first stage diffuser assembly; a second stage diffuser assembly downstream of the return channel assembly; wherein the inlet guide vane assembly, the first stage diffuser assembly, the return channel assembly, and the second stage diffuser assembly each have a respective set of vanes; wherein each respective set of vanes is configured with a respective orientation angle that can be varied independently of one another.
 16. The compressor of claim 15, wherein the drive section includes a stepper motor assembly operatively engaged with the respective sets of vanes of the inlet guide vane assembly, the first stage diffuser assembly, the return channel assembly, and the second stage diffuser assembly.
 17. The compressor of claim 15, wherein the drive section is hermetically sealed.
 18. The compressor of claim 15, wherein the controller section is hermetically sealed.
 19. The compressor of claim 15, wherein at least one the inlet guide vane assembly, the first stage diffuser assembly, the return channel assembly, and the second stage diffuser assembly includes: a unison ring operatively engaged to the drive section; a plurality of driver arms operatively engaged with the unison ring and with the respective set of vanes; wherein, when the drive section is activated, the plurality of driver arms activate the respective set of vanes.
 20. The compressor of claim 15, wherein: the drive section includes a stepper motor assembly; wherein the stepper motor assembly includes at least one pair of stepper motors; wherein the at least one pair of stepper motors is operatively engaged to one of the inlet guide vane assembly, the first stage diffuser assembly, the return channel assembly, and the second stage diffuser assembly. 